Controlling thermal expansion of mask substrates by scatterometry
US6654660B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 2002 |
| Grant date | Nov 25, 2003 |
| Priority date | — |
| Expiry date | Nov 4, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70875
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
One aspect of the present invention relates to a system and method for controlling thermal expansion on an EUV mask during EUV photolithography. The system includes an EUV photolithography system for irradiating one or more layers of a wafer through one or more gratings of a patterned EUV mask, whereby heat accumulates on at least a portion of the patterned EUV mask during the irradiation of the one or more layers of the wafer; an EUV mask inspection system for monitoring the one or more gratings on the mask to detect expansion therein, the inspection system producing data relating to the mask; and a temperature control system operatively coupled to the inspection system for making adjustments to the EUV photolithography system in order to compensate for the detected expansion on the mask. The method involves employing feedback and feed forward control to optimize the current and future EUV photolithography processes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.